Safe by the Marshal's Side

This is an Apple Books audiobook narrated by a digital voice based on a human narrator.
HER LIFE IS ON THE LINE 

For a year, U.S. marshal Hunter Davis has protected witness Annie Delacorte and her toddler daughter. But now, someone is determined to stop Annie from testifying against the men who killed her husband. To guard Annie, by-the-book Hunter will have to break a promise to himself: to not get emotionally involved. After all, he already cares more deeply than he ever imagined for the sweet family of two…a family he'll do anything to keep safe and sound by his side. 

Witness Protection: Hiding in plain sight